The invention provides a method for the elimination of drift in vector sensors. To set notation, a vector sensor is understood to be measuring a physical vectorial quantity S in an input energy domain D.sub.i by converting S into a signal in an output energy domain D.sub.o. In particular, we think here of electric or electronic sensors for the measurement of gas flow or pressure. Thus, sensors are seen to simultaneously possess a state A in the input energy domain D.sub.i and a state B in the output energy domain D.sub.o.
The new method of operation concerns the real-world application of sensors in the presence of imperfections. Imperfections are generally present in both the sensor itself and, in the case of active sensors, in the biasing of the sensor and its output amplifiers. While ideal sensors as abstract devices possess zero sensitivity for physical quantities other than S, sensors in the real-world possess imperfections due to technological limitations and, consequently, possess finite sensitivity for quantities other than S. Errors in the measurement of S due to finite sensitivity to quantities other than S are manifest in the form of offset with unpredictable behavior. The resulting drift in offset persists additively as drift in the output signal, when the input signal, S, is kept constant. Typically, the resulting offset is predominant over noise, i.e., S/offset&lt;&lt;S/noise, so that offset defines the lowest limit at which S can be reliably measured. In other words, offset typically determines the dynamic range of the sensor at hand, rather than noise. We remark that drift in the sensitivity of a sensor to its measurand S does not influence the dynamic range of the sensor. For this reason, only the forementioned drift in offset, i.e., additive drift is considered here.
The current approach towards elimination of drift is taken by a continuous effort towards ever more precise manufacturing processes. In particular, modern manufacturing processes involve special correction techniques such as laser trimming, with which imperfections resulting from the basic production process are greatly reduced. In such approach, the final performance of the sensor is determined by the quality of the overall production process. With our new method, proposed below, technological limitations are of secondary importance.